In my view rFactor is much more alive then LFS just because of how moddable rFactor is and the large mod community rFactor has. Ok, surely much of the tracks and cars are fastmade converts from earlier ISI games, but there is some really great tracks and cars too and more is coming.
I havent touched LFS for over a year now because there is no new content, just a few minor updates that doesnt do much. It`s still in alpha mode and still no tools for modders. So for me LFS is pretty much dead, i dont want to rerun the same old fantasy tracks that i hardly like anyway.